Ausscheidungshärtbarer Schneidwerkstoff mit Hartphasen

Translated title of the contribution: Precipitation hardening cutting tool material containing hard particles

Christoph Turk

Research output: ThesisDoctoral Thesis

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Abstract

The powder metallurgically produced Fe – 25 m% Co – 15 m% Mo alloy exhibits high hardness and tempering resistance due to precipitation hardening by nm-sized (Fe,Co)7Mo6 µ-phase particles. The dispersion hardening of this alloy is limited, because of the fact that carbides and borides interact with the base alloy, thus changing the precipitation behavior of the µ-phase. Hence, in this thesis the processing of a metal matrix composite based on the Fe – 25 m% Co – 15 m% Mo alloy has been evaluated in terms of feasibility and producibility. The application of different alloying techniques has led to a homogenous distribution of titanium nitrides. The microstructure and the mechanical properties of the metal matrix composites have been characterized. Thereby, high resolution technique as well as hardness, fracture toughness and ball-on-disc tribology testing have been used to evaluate the properties of the metal matrix composites. In addition to this, a special heat treatment of the Fe – 25 m% Co – 15 m% Mo alloy has led to a unique microstructure of the Fe – 29 at% Co matrix. Here, nm-sized B2-ordered FeCo domains are formed within the matrix. With high resolution techniques such as atom probe tomography and transmission electron microscopy it could be proved that these microstructural attributes cause an embrittlement of the alloy. To overcome this problem, well defined heat treatments have been developed to prevent B2-ordering and to improve the ductility of this alloy.
Translated title of the contributionPrecipitation hardening cutting tool material containing hard particles
Original languageGerman
QualificationDr.mont.
Supervisors/Advisors
  • Clemens, Helmut, Assessor A (internal)
  • Leitner, Harald, Co-Supervisor (external)
  • Bernhard, Christian, Assessor B (internal)
Publication statusPublished - 2016

Bibliographical note

embargoed until 25-11-2021

Keywords

  • FeCoMo-alloy
  • (Fe
  • Co)7Mo6
  • µ-Phase
  • Order transition
  • Titanium nitride
  • Alloy development

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